Flotation of granular ores



u van-m United States PatentO No Drawing. Filed Dec. 19, 1958, Ser. No. 781,462 C I, Claims. (Cl. 209-166) The present inventionrel'ates to the separation of min erals'in granular form. More particularly, 'it' relates to the separation of a granular miiiture of minerals by selective flotation of a component thereof. In one embodiment, it relates to th flotatio'n of sylvite from granular sylvinite of the type occurring in the Carlsbad, New Mexico, area. i The separation of mixed minerals into their component species by selective flotation is now a well-established procedure in the minerals beneficiation'art. In all cases, it is'nece'ssary for the mineral to be crushed or'otherwise reduced in size sutficiently to liberatethe mineral components from one another, and it is generally necessary for'the mineral to be crushed-to a particle size not greater than about 30 mesh in order to carryout a success-hi1 flotation. Larger particles are much-more diflicult to separate by flotation; since it is correspondingly, more diflicult for the airbubbles to become attached thereto in a quantity sufliciently great to lift the particles.

For many purposes however, it is most undesirable to reduce the mineral to powdery form. In the manufacare and" utilization of fertilizers, for example, which commonly include phosphate rock and sylvite or other potash mineral, the use of such materials in finelydivided form gives rise to'caking and dusting problems, so that granular'materials are distinctly preferred, andthe demandtherefor has greatly expanded within recent years..

A need has therefore existed for a method of beneficiating such materials in granular form, so that they are di-;- rectly available to the market without any necessity for separating them first inpowderedform and then-reconverting theminto gr'anular'fo'rm.

Methods have already been devised which achieve flotation of granular, materials to some extentf su'ch' methods, generally subject an aqueous slurry of the} desired mineral to aeration'in t-hepresence of a selective reagent such' as an. amine or a fatty acid, 'a frothing agent such as'lan aliphatic alcohol of intermediate molecular weight,- and a' non-saponifiable oil'such'as crude petroleum, .;fuel,

oil,- or'jkerosene. These methodsare reasonably etfective, but leave much to bewdes ired infterms of product recov-; ery and product quality; 'Ihe present invention is an;im provement 1.11 such; a process, whereby the product recovery is-increased and the product quality is improved.-

,One object of the present'invention is to separate the components of a granular mixture of substances.

Anotherobject isv to improve the .flotation of granular mixtures; Y Li 1 Another object is to separate granular ores 'int'o their component substances. 1

'Anj ther objectisto separategranular 'sylvite in improved yield and quality from c oar se granular sylvinite.

Another" object is tofimprove thequality of flotationgrade granularsylvite. v Other'objects of the invention will be apparent from the present description and claims.

I that the oils conventionally employed in specifications-noted above.

I PatentedJan. 9, 1962 The present invention achieves a more selective and more complete flotation of a desired ore component from a; granular-mixture thereof by adding to the flotation mixture a viscous petroleum oil having certain critical characteristics and specifications. In order to improve the product grade and recovery, the oil should have a pour point of 50 F. to -'F., a viscosity above about 100 SSU at F., andbelow 300 SSU, preferably above about SSU, and, should belargely a high-boiling material, having a distillation temperatureabove about 500" F. at the 10% distillation level. wlf it, is further desiredv to avoiddarkening of the product during the final drying operation, the oil should. meet additional specifications. Specifically, it should be largely distillable, leaving a residue of not more than about 15% i and preferably not more than about 5%. It should have a distillation end point at ordinary pressure below about 1000f vF., preferably below about 900 F. It should'have a Conradson carbon below about 5% and preferably below about 1%. It should desirably, but not necessarily, be comprised of 35% to 100% paraflinic hydrocarbons-"It can contain up to 65% aromatic and naphthenichydrocarbons without adversely affecting flotation.

The foregoing specifications are summarized and ampli- Unsulfonatable materials, percent Over 35. y Analysis, percent- I l f I Aromatics plus naphth'en'es f (l-65. Paraflins 35-100. Pour point, F... s 50 to'120. 1

From the foregoing specifications it will be ap parent tionare incapable of producing the improved results of th elpresent invention. Crude oils of various types are too wide in boiling range, and are often too high in asphaltic content for optimum flotation performance.

are actually harmful. 'Diesel ,oil fractions produce float concentrations of high analysis, but with very low recovery. Other light fuel oilsbehave somewhat similarly.

' Suitable oil fractions for use in the present invention include the so-called gas oils, lubricating. oil stocks, and

paratfinor wax distillates obtained in the distillation of crude oils andin the redistillation of cracked stocks and heavy distillates. All of these materials produce theim proved results-of the invention, .sollongas they meet the The oil is employediin a proportion betweeniabout 2 and about Spounds per ton of solids. Somewhat lower proportions may be employed if desired, but at a penalty with respect to product-recovery; and somewhat higher proportions may be employed if desired, but generally with some degree of reduction in product grade.

In one embodiment ofthe invention-a sylvinite ore is crushed to liberation of the sylvite constituent, sized to around -10 +28 mesh, placed in brine (Lesa saturated Gasoline and kerosine fractions produce negligible flotation and 3 aqueous solution of sylvinite ore), deslimed, slurried to about 65% solids, reagentized with an aliphatic amine such as n-laurylamine in the form of .its acetate salt, and subjected to a conventional froth flotation in the presence of methyl isobutyl carbinol as a frothing agent and in the presence of a viscous petroleum fratcion as hereinabove described. The float concentrate, comprising largely sylvite, is withdrawn, dewatered, washed if desired, and dried. Excellent recoveries, around 80-90% or higher, are obtained, and the produet has an analysis around 60% K 0.

The invention is applicable generally to the flotation of granular ore mixtures, and'is employedin'conne'ction with conventional techniques for such purpose. The granular ore, preferably after being sized and deslimed, is made into a slurry witha suitable brine at a t'otal solids levelof about 65% by weight or higher,- the maximum proportion being limited so as to obtain a" fluid slurry. Into this mixture is incorporated a suitable reagent, the type of reagent being chosen according to the nature of the ore and the particular component which is 'desiredto be floated. If, for example, sylvite is to be floated frorns'y'lvinite ore or from sylvinite-langbeinite' mixed ore, a cationic reagent is employed, such as'n-laurylamine, indodecylamine, or other aliphatic amine, preferably in the form of'the acetate, hydrochloride, or other water-soluble a'cidadditionsalt. The choice or a suitable flotationre agent in a given'case is well known-to the'art, an'd does not form a novel partof the'p-re'sent invention. I

It is also conventional to incorporate in the flotation mixture a suitable frothing agent, such as an aliphatic alcohol of intermediatemole'cular' weight creame a preferred example being methyl 'isobutyl carbinol. Other frothing agents are des-c'ribe'din the art.

A preferred type of oil for us'ein thepresent invention is a fractionator still bottoms obtained in the ;fraction'a-' tion of a catalytic cracking unit product in refining crude oil from Eddy and Lea Counties, New Mexico', at the Malco Refinery, Artesia, New Mexico. H In obtainingsuch a materiahcrude oil is first distilled at reduced pressure until an overhead vapor temperature of about 700 F. is attained; The overhead fraction obtained by vacuum distillation at about 700 F. is termed vacuum gas .oil and is asuitable flotation reagent. This stock oil is fed to a catalytic cracking unit from which fractionato-r bot-toms, a preferred flotation oil, is obtained.

The following table lists pertinent physicaland chemical properties'of a typical fractionator bottoms and a typical vacuum gas oil suitable for use in the present invention:

Pour point, F; Index of refraction",

Sp. gr., (SO/60F Ash, percent Conradson carbon percent Sulfur, percent Unsultonatable material, percent. Molecular weight; Analysis:

Parafiins-l-naphthenes Aromatics It is feasible 'in many cases to? efnplov'a blend of oils to improve one or more characteristic's'of the fic wtat'ion product. It has been found, for example, that ablend'of a light'lube oil stock 'anda crude oil fractionator bottoizny in around 50;50 ratio by volume gives higher productrecovery and grade than either component alone. For such a blend, it is advantageous to employ a distillate fraction with a fractionator bottoms fraction, the latter serving to maximize the viscosity, while the former reduces the proportion of color-forming bodies. Blends in various proportions may of course be employed, depending upon the color tolerance of the product and the desired product recovery.

The invention Will be more readily understood from the following operating examples.

1 A flotation-'grade crude oilobtained from LynchL'St ation, Lea County, New Mexico, was fractionally distilled into the following five fractions:

Percent (by volume) Gasoline vl0 Kerosi'ne 10 Diesel oil, ""10 Light lube stock 24 Still bottoms 4'6 Flotation tests were 'carried outoneach fraction, employv ing a thoroughly deslimed -8 +28 m wh sy-lvinite ore fraction -containir 1g 17.4% K C in ,-a satu- 1'atd .bn'ne at 65% solids content. The slurry was,reagentized with TD. amine (Armeen TD, n-octadecylamine) a t 0.8 5 pound per ton. Methyl isobutyl carbinolwas used as a frothing agent in the proportion of 1.1 lbs/ton. Theioil was used in the proportion of l0.3lbs./ton., The tests were carried out according to conventional procedure, using a Fagergren laboratory test machine adapted for granular flotation. The results were as follows:

, mixedbase crude oil conventionally employed for fgraiiin K20 Content 3 Oil Recovery Remarks Concen- Tails trate 1 V Percent: Percent Percent Crude 60.9 3.1 6.6 'OOIllJlOlTSit.

' Notmeas- Poor Flotation.

- Do. Natural-color;

, concentrate. o; Bottoms Darlg color, conc nt at Ltslbe l-Bottor'ns, Improvedcolor 1 concentrate.

Example 2; I v A plant'-scale 'test was'carried "to compare paraflinic fractionator bottoms" material produced at" the Malco 'Oil Co. refineryfat Artesi'a, New Mexico, witha lar flotation or sylvite sylvinite. The flotation feed was 35 tons per hour of deslimed 8 +28 mesh sylv nitfe ore havingia "grade of 15.6% K O,:slurried'in sat 'ate'd' brineto 65%"solids" for conditioning, reagentii TD-Armeen 'octadecylar'nine hydrochloride, and eni'ploy in'gmethyl i'sobu'tyl carbinof as the frothing'"agent.

During aft-day period employing crude oil, an 'indi cated recovery of 83.3% was obtained withan afn'ine consumption of 0.99 lbL/t'on, an alcohol usage of .048

v I lb./ton and an oil usage of 4.5 lbs/ton. 0

During the ensuing four days, employing thefractionator bottoms, an indicated recovery of 86.3% was db-,. tained withan amine usage of' '0.84 lb-./to'n, an alcohol usage of .030 lb.-/ton, and an oil usage of 3.7 lbs/ton.

. During the four days, after, usageof the crude .oil had been resumed, the indicatedrecovery wasagain 83.3%. with an amine usage of 0.95 lbt/ton, an alcohol usage of .048 lb./ tonand an oil usage of' ifi lbs .(ton.' I A e 5 During the test period employing fractionator bottomsi' the"t ailir'igs contained an averageof onljlfiqh K Q' WIII' Q. the unleached concentrat'qnieiiicd 563% K 0."

Example 3 Tests were similarly carried out to compare the fractionator bottoms with a vacuum gas oil from the same refinery. The results were as follows:

The foregoing examples refer to a number of starting materials and a number of specific instances of the class of oils to which the present invention relates. It is to be understood that such matters are illustrative only, and are not intended by way of limitation. Numerous other examples of the invention and alternative ways and aspects in which it can be applied will readily be apparent from the foregoing description to those skilled in the art.

The invention is generally applicable to the separation of the components of coarse granular ores such as sylvinite, langbeinit'e, carnallite, polyhalite, mixed sylvinitelangbeinite ore, phosphate pebble ore, and other ores which can be separated by flotation at particle sizes larger than those normally used for froth flotation. The foregoing description refers principally to the treatment of sylvinite ores, but it will be recognized that the invention is equally applicable wherever a product of large particle size is desired, for example, a Florida phosphate ore of -3 +35 mesh size. The present process requires a feed material of a particle size not greater than about 3 mesh, and sufliciently small to effect economical liberation of the desired material from the gangue. It also requires that the materials be separable by flotation means. Except in these respects, the invention is not limited as to starting material.

The following claims particularly point out and distinctly claim the subject matterof the invention:

1. In a process for separating the components of a granular potash ore wherein one component of said ore is selectively floated in the presence of a selective reagent for said component, a frothing agent, and a petroleum oil fraction, the improvement which comprises em.- ploying as said fraction a petroleum fraction having a viscosity at 130 F. greater than about 100 SSU, more than 35% unsulfonatable materials, and a distillation range with a point above about 500 F.

2. A process as in claim 1 wherein said petroleum oil fraction has a viscosity at 130 F. between about 100 SSU and about 300 SSU.

3. A process as in claim 1 wherein said petroleum oil fraction has a Conradson carbon below about 5% and a distillation range having an end point below about 1000' F.

4. A process as in claim 1 wherein said petroleum oil fraction has a Conradson carbon below about 1% and a distillation range having an end point below about 900 F.

5. A process as in claim l wherein said petroleum oil fraction is a gas oil fraction.

6. A process as in claim 1 wherein said petroleum oil fraction is a lube oil fraction.

7. A process as in claim 1 wherein said petroleum oil fraction is a wax oil distillate fraction.

8. In a process for separating the components of a granular potash ore having a particle size between about 3 and about 35 mesh wherein one component of said ore is selectively floated in the presence of a selective reagent for said component, a frothing agent, and a petroleum oil, the improvement which comprises employing as said oil a crude oil distillation residue having a viscosity at 130 F. greater than about 100 SSU, more than 35% unsulfonatable materials, and a distillation range having 7 a 10% point above about 500 F. and an end point below about 1000 F.

9. In a process for separating the components of a granular potash ore having a particle size between about 3 and about 35 mesh wherein one component of said ore is selectively floated in the'presence of a selective reagent for said component, a frothing agent, and a petro leum oil, the improvement which comprises employing as said oil a blend of a crude oil distillation residue and a lube oil fraction, said blend having a viscosity at 130 F. greater than about 100 SSU, more than 35% unsulfonatable materials, and a distillation range having a 10% point about 500 F. and an end point below about 1000 F.

10. In a process for selectively floating sylvite from granular sylvinite ore, which process comprises sizing sylvinite to the range of about 3 +35 mesh, d-esliming and then slurrying with a saturated sylvinite brine in a proportion to produce a fluent slurry containing above about solids, incorporating therein a cationic reagent, a frothing agent, and a petroleum oil, and subjecting said slurry to aeration to selectively remove the sylvite as a froth concentrate, the improvement which comprises employing as said petroleum oil a petroleum fraction having a viscosity at 130 F. above about SSU, more than 35% unsulfonatable materials, a distillation range having a 10% point above about 500 F. and an end point below about 1000 F., and a Conradson carbon below about 5%, whereby the grade and recovery of said sylvite are substantially improved, and whereby discoloration of the product is largely avoided.

References Cited in the file of this patent UNITED STATES PATENTS 1,830,908 Luckenback 'Nov. 10, 1931 2,420,476 Greene ct al. May 13, 1947 2,839,192 Monson June 17, 1958 

1. IN A PROCESS FOR SEPARATING THE COMPONENTS OF A GRANULAR POTASH ORE WHEREIN ONE COMPONENT OF SAID ORE IS SELECTIVELY FLOATED IN THE PRESENCE OF A SELECTIVE REAGENT FOR SAID COMPONENT, A FROTHING AGENT, AND A PETROLEUM OIL FRACTION, THE IMPROVEMENT WHICH COMPRISES EMPLOYING AS SAID FRACTION A PETROLEUM FRACTION HAVING A VISCOSITY AT 130* F. GREATER THAN ABOUT 100 SSU, MORE THAN 35% UNSULFONATABLE MATERIALS, AND A DISTILLATION RANGE WITH A 10% POINT ABOVE ABOUT 500* F. 